Filler metal

About: Filler metal is a research topic. Over the lifetime, 11152 publications have been published within this topic receiving 86590 citations.

Effects of Silver Coating Covered with Copper Filler on Electrical Resistivity of Electrically Conductive Adhesives

Abstract: Electrically conductive adhesives (ECAs) are usually composed of conductive metal fillers and polymeric resin. For the metals fillers, silver is the most commonly used due to its high electrical and thermal conductivities, and chemical stability. Recently copper can be a promising candidate for conductive filler metal due to its low resistivity, low cost and good electro-migration performance. In this study, to overcome the problem of high electrical resistance associated with the oxidation of copper, copper particles were coated with silver, and the silver-coated copper was tested as a filler metal. In particular, the effect of silver coating on the electrical resistivity of ECAs just after curing and after reliability tests was investigated. It was found that the electrical resistivity of ECA using silver-coated copper filler was much lower and more stable than that of ECA using pure copper filler after curing and after reliability tests.

Apparatus for welding thermoplastic materials

Abstract: An improved apparatus and method for joining two or more thin sheets of thermoplastic materials along a welded seam includes a welding assembly and a means for feeding the thermoplastic sheets to the working area of the welding assembly. The welding assembly includes a heated platen welding press coupled with a welding tool, an energy generator electrically connected to the welding tool and control means electrically connected to the welding press, the welding tool and the energy generator. The welding press includes a pair of opposed platens, means for heating each of the platens and pressing means for displacing at least one of the opposed platens in the thickness direction of the thermoplastic sheets. Pressure is applied to the thermoplastic sheets by using the pressing means to displace at least one of the heated platens in the thickness direction of the thermoplastic sheets. Heat produced by the heating means is then transferred to the thermoplastic sheets by the heated platens to raise the temperature of the thermoplastic sheets in the area of the welded seam to a first predetermined temperature which is below the softening temperature of the thermoplastic materials. High frequency energy produced by the energy generator is then conducted to the thermoplastic sheets by the welding tool to raise the temperature of the thermoplastic sheets in the area of the welded seam to a second predetermined temperature which is above the softening temperature but below the melt point of the thermoplastic materials. Conduction of the high frequency energy is then discontinued so that the thermoplastic sheets fuse together along the welded seam under applied pressure. Application of the pressure is then discontinued so that the welded thermoplastic sheets may be removed from the welding assembly.

Influences of phosphorus and sulphur on ductility dip cracking susceptibility in multipass weld metal of alloy 690

Abstract: The influence of P and S on ductility dip cracking susceptibility in the reheated weld metal of alloy 690 was evaluated by the spot Varestraint test using different alloy 690 filler metals, while varying the contents of P and S The ductility dip cracking susceptibility was reduced with a decrease in the content of P and S in the filler metal; the amount of (P+1·2S) in the weld metal should be limited to 30 ppm in order to prevent microcracking in the multipass weld metal A numerical simulation of cosegregation behaviour of P and S revealed that both elements were segregated at the grain boundary in the ductility dip temperature range during multipass welding A molecular orbital analysis has suggested that ductility dip cracking can be attributed to grain boundary embrittlement due to grain boundary segregation of P and S

Fatigue of Welded Magnesium Alloy Joints

Abstract: Magnesium alloys have attracted special attention of researchers working in transportation industries because they are the best lightweight structural materials with a relatively high-strength to weight ratio and excellent technological properties. Enhancement of structural application of such a structural material depends on the ability of construction by welding. The welding of magnesium alloys has been investigated widely. Results indicate that FSW (friction stir welding) and TIG (tungsten inert gas arc welding) are successful welding methods for magnesium alloys and aluminum alloys. 1–4) Reliability is their salient attribute, especially for use in the transportation industry. Therefore, the clarification of fatigue properties must precede application of joining by welding. 5) This study investigated the factors which affect the fatigue strength of the welded commercial magnesium alloy joints as welded surface. Investigated alloys were extruded or rolled AZ31 and AZ61. The welding processes used in this investigation were TIG and FSW. Joint efficiencies (%)

Mathematical models for control of weld bead penetration in the GMAW process

Abstract: This paper presents the effects of welding process parameters on weld bead penetration for the gas metal arc welding (GMAW) process. Welding process parameters included wire diameter, gas flow rate, welding speed, arc current and welding voltage. The experimental results have shown that weld bead penetration increased as wire diameter, arc current and welding voltage increased, whereas an increase in welding speed was found to decrease the weld bead penetration. However, the weld bead penetration is not affected significantly by gas flow rate changes. Mathematical equations for study of the relationship between welding process parameters and weld bead penetration have also been computed by employing a standard statistical package program, SAS.